Grain size trends in relation to net sediment transport pathways are examined, using sorne cornmonly-used grain size pararneters. The results of the model are compared with the net sediment transport pathways established on the basis of the bedfonn asymmetry. The 3 types of trends are calculated using an increasing characteristic distance and differents grids of seabed sediment samples. lt is shown that : (1) the characteristic distance defined by Gao et Collins (maximum spatial sampling interval) changes with these two factors to a maximal value; (2) in an heterogeneous sedimentary environment, the correlations between calculated vectors and observed transport pathways are better by using sand size distributions and (3) the residual pattern rises to sixty percent of correlation with the bedfonns asymrnetry.